Film support coated with polyester and gelatin-silver halide emulsion

ABSTRACT

An article comprising a cellulose ester- or polyethylene terephthalate-based substrate, overlying and in contact with the substrate an adhesive coating consisting of the reaction product of a triepoxide selected from the group consisting of triglycidyl cyanurate, triglycidyl isocyanurate, and tri-(2,3-dioxypropyl) isocyanurate with an aliphatic or aromatic dicarboxylic acid containing up to 10 carbon atoms in its molecule in molar proportions of the triepoxide to the dicarboxylic acid of about 1:2, and overlying and in contact with the adhesive coating a coating of a gelatin-silver halide emulsion.

Patent [191 Richter et a1.

FKLM SUPPORT COATED WITH POLYESTER AND GELATlN-SIILVER HALIIDIE EMULSIONInventors: Lothar Richter; Georg lEichhorn,

both of Berlin-Kopenick, Germany VEB Filmfabrik Wolien FotochemischeWerlre Berlin, Berlin, Germany Filed: Sept. 26, 1972 Appl. No: 292,474

Related U.S. Application Data Continuation of Ser. No. 60,632, Aug. 3,1970, Pat. No. 3,694,212, Continuation of Ser. No. 630,840, April 14,1967, abandoned.

Assignee:

US. Cl. 96/87 1R, 117/34 Int. Cl G03c 1/80 Field of Search 96/87 R;l17/34 3,128,265 4/1964 Caldwell 117/145 X Primary Examiner-Ronald H.Smith Attorney, Agent, or Firm-A. C. Nolte, Jr.; Edward B. Hunter; C.Bruce Hamburg [57] ABSTRACT An article comprising a cellulose esterorpolyethylene terephthalate-based substrate, overlying and in contactwith the substrate an adhesive coating consisting of the reactionproduct of a triepoxide selected from the group consisting oftriglycidyl cyanurate, triglycidyl isocyanurate, andtri-(2,3-dioxypropyl) isocyanurate with an aliphatic or aromaticdicarboxylic acid containing up to 10 carbon atoms in its molecule inmolar proportions of the triepoxide to the dicarboxylic acid of about1:2, and overlying and in contact with the adhesive coating a coating ofa gelatin-silver halide emulsion.

1 Claim, N0 Drawings FILM SUPPORT COATED WHTIHI POLYESTER ANDGELATliN-SILVER HALIDIE EMULSION This is a continuation of applicationSer. No. 60,632, filed Aug. 3, 1970 now US. Pat. No. 3,694,212 which, inturn, is a continuation of application Ser. No. 630,840, filed Apr. 14,1967, now abandoned.

In the photographic industry films and foils have been prepared for sometime, which consisted substantially of cellulose derivatives serving assupport for light sensitive gelatino-silver halide emulsions.

In this process, it was a major difficulty to achieve sufficientadherence of the hydrophilic, light-sensitive layer to the support.

In general, attempts have been made to overcome the above difficulty byproviding the support with an intermediate coating providing in this waythe connection between support and light sensitive emulsion. When thisis done the adhesion between support and photographic emulsion must beso strong that a separation will not take place either in the dry or inthe wet state.

When supports made of high molecular thermoplastic foils are used, thesetoo have insufficient adhesion to the light-sensitive emulsion;moreover, they cause difficulties in the preparation of an intermediatelayer owing to their resistance to chemicals.

In one of the older conventional processes, for example, gelatin wasdissolved in an organic solvent and applied to the support preferablytogether with a high molecular hydrophobic substance, such as celluloseacetate. In that manner, a continuous layer is formed on the surface ofthe support which has sufficient hydrophilic characteristics owing tothe content of gelatin and thus imparts adhesive power to the support.When in using this method a suitable pH-value is adjusted in theadhesive layer, light sensitive emulsion layers of sufficient adhesivepower in the wet state will be obtained, even when they contain ahardener.

A further possibility of pre-treating a film support is to apply to thesupport thin layers of plastics containing reactive groups in themolecule. As a rule, the plastics are copolymers of maleic anhydridewith various vinyl monomers.

A further process for obtaining sufficient adhesive power consists in achemical modification of the support by saponification or oxidation.

However, the known methods have disadvantages in their practicalapplication. Thus, for example, a neutralization of the support has tofollow the saponification or oxidation, respectively, and additionalwashing operations are necessary. The use of gelatin presents particulardifficulties in industrial application. Moreover, difficulties appear inthe re-use of scraps of film, so that a general introduction of thesemethods did not appear promising for practical purposes.

It is an object of this invention to provide a process for pretreatingfilm support which makes it possible to avoid the cited disadvantages.

SUMMARY OF THE INVENTION As mentioned before, the present inventionrelates to a pretreatment of film supports made of cellulose esters andhigh molecular weight thermoplastic foils by providing the supports witha surface coating in such a manner that a sufficient bonding is achievedbetween support and light-sensitive emulsion, not only in the dry state,but also in the wet state; in addition the invention provides for easyprocessing of film and re-use of waste products.

It was found, that one way to avoid the disadvantages of known methodsconsists in using polyester containing free epoxy groups in theirmolecules for preparing the adhesive layers. The support provided withthese substratums has, after coating with an emulsion, an excellentadhesive power in the dry and wet states. Contrary to the supportprovided with the usual plastic substrata, the support pretreated withpolyester substratum can be dissolved without any difficulty in suitablesolvents, such as methylene chloride. In this manner, a reuse of scrapsof film is possible; such recovery is an important economical factor inthe photographic industry.

To prepare the polyesters, compounds containing at least three epoxygroups per molecule are reacted with aliphatic or aromaticpolycarboxylic acids in such a manner that some free epoxy groups willremain in the molecule, which are capable of reacting with the gelatinof the photographic emulsion. One of the possible methods is to reactone mole of a dissolved triepoxide with one mole of a dicarbocylic acid,whereby one epoxy group per unit remains free for reaction with gelatin.

It was further found, that the above mentioned disadvantages can beavoided, for example, when for the preparation of substrata polyestersare used which contain carboxylic groups in the molecule. A supportequipped with such substrata has an excellent adhesive power in the dryand the wet state when coated with an emulsion.

To prepare suitable polyesters, polyalcohols or polyepoxides containingat least three functional groups are reacted with aliphatic, aromatic orhydroaromatic polycarboxylic acids in such a manner, that freecarboxylic groups are present in the reaction product, one carboxylicgroup per unit being sufficient to give good results in adhesive power.

One of the possible methods consists of a reaction of one mole of adissolved triepoxide with two moles of a dicarboxylic acid in such amanner that one carboxylic group forms an addition product with eachunit of triepoxide.

The described reaction is preferably effected with polycarboxylic acidscontaining up to 8 C-atoms in the molecule. Particularly suitable are:maleic acid, succinic acid, itaconic acid, phthalic acid as well as thederivatives or mixtures of the acids. As epoxide components we may usestable derivatives of cyanuric acid or isocyanuric acid, respectively.

A further possibility of operating consists of reacting polyoxycompounds containing at least three functional groups in the moleculewith polycarboxylic acids or their anhydrides whereby a polyestercontaining one free carboxylic group per unit is obtained.

Suitable reaction media are, among others, dioxane, ethylenechlorohydrin, dimethylsulfoxide, cyclohexanone, methylene chlorohydrinand dimethylformamide. As solvents for the polyester we may usemethan'ol, acetone, methylene chloride, dichlorethane or other solventsswelling the support, or mixtures of such solvents. The applicability ofthe aforementioned compounds is not limited to the pretreatment of thesupport made of cellulose triacetate; excellent adhesive layers are alsoobtained on supports made of polyethylene terephthalate when, inaddition, aromatic oxycompounds, halogenated aromatic oxy-compounds,halogenated aliphatic carboxylic acids or alkane bisphenols orderivatives of these compounds are added to the solution of thesubstratum.

EXAMPLE 1 14.9 g triglycidyl cyanurate and 5.8 g maleic acid arerefluxed in 40 ml ethylene chlorohydrin for one hour. After that time,the reaction is completed and the reaction mixture still contains onefree epoxy group per mole triglycidyl cyanurate.

50 ml of this solution are diluted with 20 ml ethylene chlorohydrin and1.93 l of a mixture of methanol and acetone (1:3), the solution isapplied to a cellulose triacetate support and dried at 80C.

After coating with an emulsion, a photographic material is obtainedhaving excellent adhesive power in the dry as well as the wet state, andthe photographic emulsion will peel off from the support at the meltingpoint only.

EXAMPLE 2 14.9 g triglycidyl isocyanurate and l 1.6 g maleic acid arewarmed up and dissolved under stirring with 40 ml dioxane. Then themixture is refluxed for three hours, after which time 2 or 3 epoxygroups of the triglycidyl isocyanurate will have reacted with the acid,and the reaction is discontinued. The excess acid aids in a furtherlinking of the plastic during the drying process of the support at atemperature above 80C. In this manner, a further increase in adhesivepower is obtained.

50 ml of the aforementioned reaction product are diluted with 20 mlethylene chlorohydrin and 1.930 1 of a mixture of methanol and acetone(1:3), applied to a cellulose triacetate support, and dried at atemperature above 80C. After coating with an emulsion, a photographicmaterial is obtained which will not peel off the support in the dry orthe wet state.

EXAMPLE 3 15 g triglycidyl isocyanurate and 10 g phthalic acid aredissolved in 40 ml dioxane and refluxed under stirring until 2.5 of theepoxy groups present per mole are esterified. The reaction is completedafter about 5 hours. This reaction product is soluble in all the usualorganic solvents, as for example methanol, acetone, methylene chloride,dichloro-ethane, and the like.

50 ml of this reaction product are diluted with 20 ml ethylenechlorohydrin and 1.930 1 ofa mixture of methanol and acetone (1:2.8),applied to cellulose triacetate support and dried at a temperature above80C. After coating with an emulsion, a photographic material is obtainedhaving an excellent adhesive power in the dry and the wet state.

EXAMPLE 4 15 g triglycidyl isocyanurate and g. phthalic acid aredissolved in 40 ml dioxane' and refluxed with stirring until 2.5 of theepoxy groups present per mole are esterified. The reaction is completedafter about 5 hours.

To 25 ml of this reaction solution are added 50 g propane 2.2-bis(p-phenol) and it is diluted with 1 liter of a mixture of methylenechloride and methanol (1:2).

This solution is applied to a film support made ofpolyethyleneterephthalate.

A thus pre-treated support has, after coating with an emulsion anddrying, an excellent adhesive power in wet and dry state.

EXAMPLE 5 297 g triglycidyl isocyanurate and 332 g phthalic acid aredissolved in 600 ml dioxane with stirring and heating. Then the solutionis further heated until the presence of only one carboxylic group can befound in the reaction solution.

50 ml of this reaction solution are dissolved in 100 m1 ethylenechlorohydrin and filled up to 1 liter with a mixture of methanol anddichloro-ethane (1:1). This mixture is applied as a coating on cellulosetriacetate.

After coating with an emulsion a photographic material is obtainedhaving an excellent adhesive power in the dry and the wet state.

EXAMPLE 6 297 g triglycidyl isocyanurate and 332 g maleic acid aredissolved in 600 ml dioxane with stirring and heating and then refluxeduntil percent of the acid have reacted. The reaction takes about fourhours.

25 ml of the reaction solution are dissolved in a mixture ofmethylenechloride and methanol (3:1 containing 75 g p-chloro-m'cresol per liter.

This solution is applied to a support of polyethylenetherephthalate. Inthis case, too, a photographic material having an excellent adhesivepower in the dry and the wet state is obtained, after having been coatedwith an emulsion.

EXAMPLE 7 92 g anhydrous glycerine, 196 g maleic anhydride and 0.5 mlboron trifluoride etherate are dissolved in 40 ml dioxane under stirringand then nitrogen was passed through the heated solution until thepresence of only one carboxylic group per unit could be detected.

50 ml of this solution are diluted with 20 ml ethylene chlorohydrin and1.930 1 of a mixture of methanol and acetone 1:3). This mixture iscoated onto cellulose triacetate support and dried at C.

After coating with an emulsion, a photographic material having anexcellent adhesive power in the dry and the wet state is obtained.

EXAMPLE 8 351 g tri-(2,3-dioxypropyl) isocyanurate, 332 g phthalicanhydride and 0.5 ml boron trifluoride etherate are dissolved in 40 mldioxane under stirring and then heated, while nitrogen is passed throughuntil the presence of only one carboxylic group per unit can bedetected.

50 ml of this solution are diluted with 20 ml ethylene chlorohydrin and1.930 1 of a mixture of methanol and acetone 112.9) and the mixturecoated onto polyethylene-terephthalate support.

After coating with an emulsion, a photographic material having anexcellent adhesive power in the dry and the wet state is obtained.

What is claimed is:

1. An article comprising a cellulose esteror polyethyleneterephthalate-based substrate, overlying and in molar proportions of thetriepoxide to the dicarboxylic acid of about 1:2, and overlying and incontact with the adhesive coating a coating of a gelatin-silver halideanurate with an aliphatic or aromatic dicarboxylic acid 5 emulsioncontaining up to 10 carbon atoms in its molecule in

